Presently, according to the most widely employed arrangements, the silencers for portable firearms are applied thereto by means of a threading action or by means of a bayonet-type coupling. In both cases, however, the application of the silencer to the firearm requires always a rotational movement of the silencer, either complete or partial and this renders the operation somewhat cumbersome and slow in execution. Furthermore, such an operation may give rise to problems with respect to the aiming or leveling sight of the firearm, especially in the case of silencers which are attached by means of threading.